Michael Caines serves up Jerusalem artichoke soup with white truffle oil on Christmas Kitchen with James Martin.

Michael: “Jerusalem artichokes have a wonderful texture, with an earthy, slightly nutty flavour. Here they blend perfectly with the luxury of the white truffle oil.”

The ingredients are: 30g butter, 70g onions, sliced, 250ml chicken stock, 400g Jerusalem artichokes, peeled and cut into small pieces, 1 bouquet garni, 250g butter, few drops white truffle oil, few drops truffle juice (optional), 1 tbsp chopped fresh chives, salt and freshly ground black pepper.